Objective lens system with five elements

ABSTRACT

An objective of the expanded Tessar type, having five elements constituting four components (two of the elements being cemented to each other to form one component), all of the components being air spaced from each other. The front two components (in the direction from the object or long conjugate side toward the image or short conjugate side) are both positive. Numerical limits or ranges are given, for certain designated features of the lens system. If a lens of this type is so designed that the designated features fall within the specified ranges, improved results are attained.

BACKGROUND OF THE INVENTION

This invention relates to an objective lens system of what may be calledthe expanded Tessar type, which type is disclosed, for example, in U.s.Pat. No. 2,105,799. The lens has a front member, designated in thedrawing and in the examples as Vgl (standing for the German wordVorderglied) and a rear member designated as Hgl (standing for theGerman word Hinterglied). The front member is made up of threeindividually air spaced lens elements, and the rear member is a doubletconsisting of two lens elements of opposite sign of power, cemented toeach other to constitute a single component. A diaphragm space isprovided between the front member and the rear member. The neighboringcemented surfaces of this doublet constituting the rear memberconstitute a collecting cement surface. In the front member, the frontelement is an unequal-sided collecting element, followed at a smallfinite air spacing by a positive meniscus which is convex toward thefront and concave toward the rear, this meniscus being followed, inturn, by an unequal-sided negative lens which has its most stronglycurved surface in the form of a surface concave toward the rear. Adispersing air lens is formed between the rear surface of the secondelement and the front surface of the negative lens constituting thethird element.

SUMMARY OF THE INVENTION

In a five element objective of the expanded Tessar type, a valuableincrease in the picture taking quality of the lens is achieved if, inorder to keep the proportion of primary abberrations small, the firstpair of collecting lenses into which the rays of light enter from theremote object are both made of glass having a refractive index (for thed-line of the helium spectrum, wavelength 5876 Angstrom units) isgreater than 1.6454. The use of such glass for the first two elementsfundamentally provides assurance that, from the very start, therefractive index proportional values of these glasses in the aberrationcoefficients of third order are in the desirable range of less than 2.55for the coefficient n/ (n-1), and less than 6.50 for the coefficient n²/( n-1)². These coefficients are respectively referred to hereafter asx' and x". The importance of keeping these values of x' and x" less than2.55 and 6.50, respectively, can be seen from the well known work by I.C. Gardner, "Application of the algebraic abberration equations tooptical design," published as U.S. Bureau of Standards Scientific PaperNo. 550, 1927, particularly equation 24 on page 95, and appendix 4, page201, value column 4.

Values within these limits are known in the art from German patent1,190,216, but have not been generally recognized in the art as beingimportant, as will be seen from Table I below, which shows these valuesof the refractive indices for the first two elements of a lens of thissame general type, according to typical prior patents, and the resultingcoefficient values x' and x", and shows in comparison thereto thecorresponding values for the examples of the present invention.

According to the present invention, a lens system of this general typeabove described should have certain other features or physicalcharacteristics not found in the prior art, which give greatly improvedresults, when these additional features are within the values or limitsstated, the lens otherwise being of the kind described above. Theseadditional features or conditions which are highly desirable, accordingto the present invention, are the following, which may be regarded asrules of design for the front pair of collecting lenses.

Feature (a). The front radii R₁ and R₂, respectively of the frontpositive lens elements L₁ and L₂, respectively, which are both of convexcurvature toward the front, are so dimensioned with such curvature withrespect to each other that the reciprocal of Gardner's curvature indexis within the range or limits of + 0.109 and - 0.275. For furtherexplanation of the Gardner curvature index, see the above cited work byGardner. The reciprocal of the curvature index for these first two lenselements may be written as σ₂, 1, which is the quotient of thedifference in radii R₂ - R₁ divided by the sum of these radii R₂ + R₁.

Feature (b₁). The relative distribution of the proportional portions ofthe Petzval picture curvature between the front lens element L₁ and thefollowing positive meniscus element L₂ is so dimensioned that thedifference in the Petzval curvature portions B - A is within the limitsor range of + 0.124 Φ and - 0.599 Φ, wherein Φ represents the equivalentrefractive power of entire lens system. The Petzval curvature portion Bis the refractive power of the second lens element divided by the indexof refraction of the glass used for this lens, that is, B = φ₂ : n₂.Similarly, the Petzval curvature portion A = φ₁ : n₁. That is, in eachcase the Petzval curvature portion of a lens element is thecorresponding lens power divided by the corresponding index ofrefraction.

Feature (b₂). The quotient (ψ BA) of the difference of the above Petzvalcurvature portions (B - A) of these two front collecting lenses dividedby the sum (B + A) of these two Petzval curvature portions is within thelimits or range of + 0.089 and - 0.625. In this connection, one may notethe recognized theory that the lens power φ_(x) for a lens of eitherglass or air of any order x is equal to the sum of the two associatedsurface powers φ_(x) + φ_(x) ', in which connection each surface powermeans φ_(x) = (n_(x) ' - n_(x)) : R_(x).

BRIEF DESCRIPTION OF THE DRAWING

The single FIGURE of the drawing is a schematic exploded diagramindicating the general configuration of the lens according to thepresent invention, and is not necessarily drawn to scale, as it isintended to be a schematic representation of all of the various specificembodiments here disclosed, even though the embodiments may differ fromeach other somewhat in specific dimensions of radii, thicknesses, andspacings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As stated above, in connection with feature a, an important feature ofthe invention is the design of the lens system in such a way that theGardner curvature index is within the limits above stated. Within thestated limits, it may be either positive or negative. Those skilled inthe art will immediately recognize, from what has been said above, thatif the Gardner curvature index is to be positive, then the front surfaceR₁ of the first lens element L₁ must be of greater curvature (that is,of less radius) than the front surface R₂ of the positive meniscus lenselement L₂. Similarly, if it is desired to have a negative value for theGardner curvature index, then the front surface R₁ must be of lesser orweaker curvature (i.e., greater radius) than the surface R₂ of thesecond lens element. If the radii of curvature of the front faces of thefirst two lense elements are exactly equal, then the Gardner curvatureindex will be zero.

By dimensioning the lens components to achieve a Gardner curvature indexwithin the limits above specified for feature a, a particularlyexcellent balancing of the dioptric effect on the course of the zonalabberations in the finitely opened parts of the beam of light can beestablished for the first time for the central and middle region ofimage field. If the above stated upper limit of a positive value of theGardner curvature index is exceeded, this would lead to enlargement ofthe longitudinal aberration deviation in the zonal inner region. If theGardner curvature index range above stated is exceeded in the negativedirection, this would lead to an increase of aberration in the region ofthe beam cross section close to the edge.

By utilizing also the above stated rule or feature b₁ with respect tothe Petzval curvature, in conjunction with feature a, it is possible toachieve a particularly suitable stretching of the residual imagecurvature over the extended field of view by dimensioning the lens tocomply with feature b₁ and at the same time to comply with feature a,there is obtained a dioptric action which is both surprising and veryexcellent, on the course of the image curvature over the entire usefulfield of view. Dimensioning the two positive lens components L₁ and L₂at the front of the lens system (these components also being designated,in the diagram and elsewhere, as components A and B) in such a way as tocomply with the above stated rule b₁ relating to the Petzval imagecurvature, one achieves for the first time a previously unknownbalancing out of the Petzval coefficients to increase the quality of thepicture image in a practical manner of carrying out the technicalembodiment. Within the range stated for this rule, if one achieves aPetzval coefficient of zero, then we have the coefficient B exactlyequal to the coefficient A, since the two have the same sign. Such avalue of zero is achieved in example 1 given below, as will be observedfrom Table II.

The extremely great increase in picture quality achieved by dimensioningthe lens system to comply simultaneously with the two rules or featuresa and b₁ in a lens system of the expanded Tessar type initiallyidentified above, will be clearly evident to those skilled in the art,after reading the present disclosure, particularly with reference to thewidened field of view. It is very important that in the pair ofcollecting lenses at the front of the objective, the front lens L₁ is ata substantially larger distance from the corresponding position of theentrance pupil EP than the positive meniscus L₂ which follows this frontlens L₁. For this reason not only do the collecting front surfaces R₁and R₂ of these two collecting lenses act toward producing extremelydifferent beam path lengths up to the stop or diaphragm, but furthermorein this connection the lens coefficients of the Petzval image curvature(and therefore A on the one hand and B on the other hand) also have theparticular importance of their position within the course of the beam intheir influence on the shape of the two astigmatic image shells and theastigmatism has the angle-corresponding difference in each case betweenthe sagittal and the tangential image point in the lateral course ofthese image shells. The above mentioned position of the entrance pupilrefers to the image of the diaphragm produced by the lens elements infront of the diaphragm, considered in a direction forwardly (opposite tothe direction of incoming light) from the location of the stop ofdiaphragm.

In order to make clear in particular this previously generallyinsufficiently known optical event even for the zonal astigmatic beamcourse, it may be stated here, under permissible simplification, that inthe concrete case of example 3 given below, the front surface vertex ofthe surface R₁ is at a distance of + 0.5062 F from the image associatedwith it of the axial base point of the stop or diaphragm, while theaxial vertex point of the front surface R₂ of the positive meniscus isat a distance from the corresponding image of the location of the stopof only + 0.2531 F. (F represents the equivalent focal length of theentire lens system.) Therefore this comparison difference for the frontlens L₁ with respect to that of the positive meniscus L₂, is practicallyexactly twice as great as in the case of the latter, since the quotientof these two comparative values of the associated pupil positions is1.99991, and thus the beam path lengths, referred to the location of thepupil, of the oblique beams is practically in the ratio of 2:1, forthese two characteristic collecting surfaces.

The feature or rule of construction b₁ teaches in detail that in itspositive range of positions, the dimensioning of the positive meniscusin accordance with the power of refraction and collection of the glass,is to be chosen such that its lens coefficient of the Petzval imagecurvature B is less than + 0.124Φ greater than the partial coefficient Aof the front lens L₁. Thus an advantageous relaxation, so important forthe obtaining of the advance or improvement, is assured in practice. Onthe other hand, in the negative range of positions of this feature orrule b₁ the Petzval lens coefficient A is greater than the coefficient Bof the positive meniscus, and in accordance with the inventive concept,is to be dimensioned in such a manner that its negative numerical valueis within the limits or range from zero to - 0.599Φ as compared with thenumerical value B meniscus the lens coefficient of the menicus L₂, inorder to make certain that the beams coming from the object and passingthrough the pair of collecting lenses are not already imparted by thefirst element L₁ an intolerably high image curvature partialcoefficient, which would lead to a rise in zonal aberration of thelateral image shells and thus counteract the intended increase inperformance.

Furthermore in accordance with the invention, in order to insure that,without any possibility of doubt, the distribution of the lens partialcoefficients of the Petzval image curvature on the two front lenselements L₁ and L₂ will be advantageous, it is desirable that the lenscomponents be so dimensioned that they fulfill also a third rule orcondition stated above as feature b₂. This third feature is related tothe second feature b₁ but is somewhat different therefrom. It relates,as already mentioned above when it was initially stated, to thereciprocal of the image curvature distribution number as the quotient ofthe difference B-A divided by the sum B+A. As already stated above, ifthis distribution number is positive, it should be within the limits orrange of + 0.089 and zero, and if negative it should be within thelimits or range of - 0.625 and zero.

These three rules or features a and b₁ and b₂ in their entirety (thatis, considering all three rules simultaneously) unequivocally set forththe principle of construction of an objective according to the presentinvention. It should be recognized, of course, that the numerical limitsabove stated are subject to the usual tolerance of plus or minus 5%, ascustomary in the optical design field when stating numerical values orranges. Also it should be recognized that we are here talking aboutimprovements in a lens system of the extended or expanded Tessar typeidentified or defined near the beginning of this specification. Theherein stated rules or features for improving performance of lenssystems of the expanded Tessar type do not necessarily apply to lensesof other types.

From the analysis of the above stated features or rules of constructionand a careful consideration of the other information given in thisdisclosure, it will be apparent to a person skilled in this art, that inagreement with recognized teaching, there is not only a definiteredundance provided by following the subsidiary condition b₂ for thesecond main feature b₁ but at the same time there is also established aframework of dimensioning which at the same time permits the maintainingof the astigmatism small in the edge portions of the extended lateralfield of view. The extreme optical importance for the total pictureperformance is in this connection now obvious (as a result of thepresent disclosure) to the person skilled in the art when he bears inmind, in accordance with the recognized but frequently disregardedteaching, that the Petzval theorem is of importance for the imagecurvature if and only if the the beam combination is punctiform evenlaterally of the axis. This teaching is stated in the standard referencework "Theorie und Geschichte des Photographischen Objektivs" (Theory andHistory of Photographic Objectives) by M. von Rohr, published by JuliusSpringer, Berlin, 1899, page 359, lines 31-34. The expression"punctiform" means that there is concerned a focusing withastigmatism-free combining of the image in the lateral parts of thefield of view.

The present new principle of construction with its requirement that allthree of the rules or features above stated be simultaneously satisfied,in the very specific type of expanded Tessar lens initially identified,has been fully confirmed in the course of extensive investigations. Thisprinciple importantly and surprisingly establishes an advance in theart, and the investigations also show at the same time that before theserules of construction were recognized, it was impossible to realize inpractice a great improvement in the picture performance. Before themaking of the present invention and the recognition of the importance ofsimultaneously fulfilling the above stated rules or features, it was atmost conceivable to obtain very small and unsubstantial improvements fora certain course of aberration, only by tolerating an extremelydetrimental or injurious increase in the aberrations of higher order forthe predominant majority of other aberrations in or outside of thecentral parts of the image. The analysis of the present invention and ofthe consequences of its dioptric effect make it possible clearly to seethat the aberration-free beam courses coming from the object within thepair of collecting lenses arranged at the front of the overall system isto be subjected only to very specifically measured portions ofaberrations during its passage through this pair of collecting lenses L₁and L₂, since the lens components following these lenses in thedirection toward the shorter conjugate or image, otherwise cannot leadto a proper compensation of image aberrations. Hence as a practicallynecessary consequence, there are disturbing residual aberrations whichoppose the desired improvement in the image, and also, if extreme typesof glass are used, unavoidable aberrations of higher order which greatlyimpair the combining of the image, if one does not design the lens inaccordance with the inventive principles here disclosed.

There have been previous proposals for increasing the pictureperformance of the five lens objective of the expanded Tessar type withwhich the present invention deals. One of these proposals, thatdisclosed in U.S. Pat. No. 2,105,799 and the corresponding Britishpatent 476,349, has become known to a wide group of experts,particularly by the publication in the supplement by K. Michel to the"Handbuch der wissenschaftlichen und angewandten Photographie" (Handbookof scientific and applied photography) published by Springer, Vienna,1943, page 28, FIG. 22. The description given therein of the variationof the aberration in the central part of the image (FIG. 22a) shows theextremely large zonal defects of spherical aberration (solid line curve)and deviation from the sine condition (dashed line curve) which clearlyconfirm the above statements. Such defects may have been entirelyacceptable for the state of the art at that time, but are no longeracceptable at the present time, when a higher quality of performance isdemanded. FIG. 22b of the above cited publication shows the astigmaticimage-point deviations for the position of the sagittal image points(solid line curve) as well as for the tangential image points (dashedline curve).

From this information given in the publication just cited, it can beseen that even with an inclination of the main beam of 20° theastigmatism reaches the critical limit of 1.0% of the equivalent focallength, increasing in the case of an inclination of the beam of 25.5° to2.09%, and thus exceeding the permissible amount which modernphotographic technique specifies for the existence of an image combiningwhich is considered to be good according to today's standards.

With a knowledge of the present disclosure of the new principle ofconstruction and its optical importance, a comparative analysis readilyshows the man skilled in the art that not only are the detailedstatements in connection with the present patent application fullyconfirmed, but that, in addition, this older form of construction offive-lens expansions of the Tessar type must necessarily have such anaberration-affected beam combination of finitely opened and finitelyinclined beam bundles that the comparative numerical values in the caseof this older objective lie far outside the characteristic framework andthe combination of features in accordance with the present invention.The present invention enables this specific type of five-lens partiallycemented objective to be designed by using the rules or features hereinstated, in a manner which is very simple for such an important increasein picture performance.

In the following data tables, 14 specific examples of lens systemsaccording to the present invention are given. In all of these examples,all linear measurements such as radii, thicknesses, and spacings arestated as proportions of the equivalent focal length (F) of the entireobjective or lens system, which is considered as unity. That is, F =1.0000. The individual lens elements are indicated, both in the exampletables and in the schematic drawing, by the letter L with a subscriptcorresponding to the number of the individual lens element as numberedconsecutively from front to rear, that is, from 1 to 5. The lenscomponents are indicated by capital letters A through D, the first threelens elements being regarded as individual components, while lenselements 4 and 5, being cemented to each other, are regarded as a singlecomponent D. For convenience of illustration, the elements L₄ and L₅ areshown in the diagram as being slightly separated from each other, butactually they are cemented to each other as shown by the designation ofzero spacing at this point, in all of the tables of specific examples.

The radii of curvature of the front surface and the rear surface of eachelement are indicated by R and R', respectively, with a subscriptindicating the number of that particular element. Positive values of Ror R' indicates surfaces convex toward the front of the lens, andnegative values indicate surfaces concave toward the front, inaccordance with customary usage. The end of the lens toward the distantobject or longer conjugate is referred to for convenience as the front,and the end toward the image (that is, toward the camera, if the lens isused on a photographic camera) is referred to for convenience as therear of the lens. The light is assumed, in accordance with conventionallens patent practice, to enter from the front, and to pass through thelens from left to right as indicated by the arrow in the lens diagram.

Axial thicknesses of individual elements are indicated in the tables bythe letter d with a subscript referring to the identifying number of theparticular lens element. Spacings between the elements are indicated bythe letter s with a subscript corresponding to the identifying number ofthe lens element in front of the space and lens element behind thespace. For example, s₁₂ indicates the space between element 1 andelement 2, and s₂₃ indicates the space between element 2 and element 3,and so on. Zero spacing indicates elements cemented to each other. Allspacings greater than zero refer to air spacings. In all examples, thespace s₃₄ between element 3 and element 4 is considered the centralspace (CS) in which the stop or diaphragm is to be located.

The index of refraction of the glass used for each element is showneither by the symbol n with a subscript referring to the individual lenselement, or by data in a column headed n_(d), the latter being used forthe sake of compactness when the data also includes the Abbe number ordispersive index, in a column headed v_(d). When an objective isdesigned for use in only a very narrow spectral range, the refractiveindex refers specifically to this narrow range. If the lens is to beused over a wide spectral range, as for example in taking colorphotographs, then instead of monochromatic image-error correction, anachromatism should be brought about over the wider spectral rangerequired. For this purpose, in known manner, the glasses are to bechosen so that the color dispersion of the glasses used, defined bytheir corresponding v value or Abbe number, serves to eliminate thechromatic deviations or errors due to the wavelengths which enter intoconsideration.

During the course of making this invention it was found, by way ofconfirmation, that upon the development of the so-called initial formsor preforms of the objective, and then in the course of the subsequenttechnical rough shaping (rough form) in known manner with the firstcorrection normally customary in the Seidel range (third order) the useof one of the standard indices of refraction can take place in a purelyroutine manner. A convenient index to use for this purpose is the indexof refraction for the yellow d-line of the helium spectrum, with awavelength of 5876 Angstrom units. Data for this wavelength iscustomarily shown in many commercial catalogues of manufacturers ofoptical glasses.

In addition to the values of the linear dimensions and thecharacteristics of the glass, the example tables also indicate, at thetop of each table, the intended relative aperture, the total field angledesignated as numeral 2w_(o) provided for, as well as the resultant backfocus s_(oo) '.

The first four examples relate to preforms in accordance with theinvention which are provided in the region of the third order withmonochromatic precorrection, the indices of refraction used in theseexamples being based on the above mentioned wavelength of 5876 Angstromunits.

The fact that the invention provides a truly novel principle ofconstruction is made clear not only by the scope of use both withrespect to relative aperture and with respect to angular extent of theimage field, but also by the fact the front element in its three-lensoverall combination can be developed either with a negative paraxialpower of its own (examples 6, 8, 9, and 10) or with a positive power(examples 1, 2, 4, 5, 7, 11, 12, 13, and 14) or with a completely freepower or refraction and therefore with an intrinsic power of 0 (example3) provided that the new rules of construction in accordance with theinvention are satisfied.

                                      Example 1                                   __________________________________________________________________________    F = 1.00000 f/2.9 2ω.sub.o = 50° s.sub.∞' = + 0.6341       __________________________________________________________________________          R.sub.1 = + 0.39000                                                     A  L.sub.1      d.sub.1 = 0.09000                                                                        n.sub.1 = 1.6810                                         R.sub.1 ' = + 0.91453                                                                    s.sub.12 = 0.00140                                                 R.sub.2 = + 0.35150                                                     B  L.sub.2      d.sub.2 = 0.07000                                                                        n.sub.2 = 1.7200                                                                      Vgl.                                             R.sub.2 ' = + 0.70339                                                                    s.sub.23 = 0.02844                                                 R.sub.3 = + 2.35386                                                     C  L.sub.3      d.sub.3 = 0.02055                                                                        n.sub.3 = 1.7850                                         R.sub.3 ' = + 0.25217                                                                    CS = s.sub.34 = 0.10163                                            R.sub.4 = + 2.50017                                                        L.sub.4      d.sub.4  = 0.028999                                                                      n.sub.4 = 1.6380                                         R.sub.4 ' = + 0.32000                                                   D               s.sub.45 = 0       Hgl.                                             R.sub.5 = + 0.32000                                                        L.sub.5      d.sub.5 = 0.115965                                                                       n.sub.5 = 1.7440                                         R.sub.5 ' = - 1.13500                                                   __________________________________________________________________________

                                      Example 2                                   __________________________________________________________________________    F = 1.00000 f/2.7 2ω.sub.o = 53° s.sub.∞' = + 0.6341       __________________________________________________________________________          R.sub.1 = + 0.3910                                                      A  L.sub.1     d.sub.1 = 0.08620                                                                        n.sub.1 = 1.717                                           R.sub.1 ' = + 0.8200                                                                    s.sub.12 = 0.00250                                                  R.sub.2 = + 0.3450                                                      B  L.sub.2     d.sub.2 = 0.07060                                                                        n.sub.2 = 1.717                                                                      Vgl.                                               R.sub.2 ' = + 0.7450                                                                    s.sub.23 = 0.02750                                                  R.sub.3 = + 2.5000                                                      C  L.sub.3     d.sub.3 = 0.02050                                                                        n.sub.3 = 1.785                                           R.sub.3 ' = + 0.2485                                                                    CS = s.sub.34 = 0.100020                                            R.sub.4 = + 2.5000                                                         L.sub.4     d.sub.4 =  0.02900                                                                       n.sub.4 = 1.638                                           R.sub.4 ' = + 0.3200                                                    D              s.sub.45 = 0      Hgl.                                               R.sub.5 = + 0.3200                                                         L.sub.5     d.sub.5 = 0.116025                                                                       n.sub.5 = 1.744                                           R.sub.5 ' = - 1.1350                                                    __________________________________________________________________________

                                      Example 3                                   __________________________________________________________________________    F = 1.00000 f/2.3 2ω.sub.o = 43° s.sub.∞' = + 0.6383       __________________________________________________________________________          R.sub.1 = + 0.4440                                                      A  L.sub.1     d.sub.1 = 0.08700                                                                        n.sub.1 = 1.6780                                          R.sub.1 ' = + 1.9000                                                                    s.sub.12 = 0.00180                                                  R.sub.2 = + 0.4530                                                      B  L.sub.2     d.sub.2 = 0.06850                                                                        n.sub.2 = 1.7440                                                                      Vgl.                                              R.sub.2 ' = + 0.5700                                                                    s.sub.23 = 0.05250                                                  R.sub.3 = - 7.2440                                                      C  L.sub.3     d.sub.3 = 0.06677                                                                        n.sub.3 = 1.7280                                          R.sub.3 ' = + 0.3076                                                                    CS = s.sub.34 = 0.12000                                             R.sub.4 = + 1.7160                                                         L.sub.4     d.sub.4 =  0.02440                                                                       n.sub.4 = 1.5810                                          R.sub.4 '= + 0.3900                                                     D               s.sub.45 = 0      Hgl.                                              R.sub.5 = + 0.3900                                                         L.sub.5     d.sub.5 = 0.08090                                                                        n.sub.5 = 1.7440                                          R.sub.5 ' = - 0.9530                                                    __________________________________________________________________________

                                      Example 4                                   __________________________________________________________________________    F = 1.00000 f/1.6 2ω.sub.o = 33° s.sub.∞' = + 0.3890       __________________________________________________________________________          R.sub.1 = + 0.576                                                       A  L.sub.1     d.sub.1 = 0.1915                                                                        n.sub.1 = 1.734                                            R.sub.1 ' = + 3.580                                                                     s.sub.12 = 0.0027                                                   R.sub.2 = + 0.454                                                       B  L.sub.2     d.sub.2 = 0.1207                                                                        n.sub.2 = 1.788                                                                      Vgl.                                                R.sub.2 ' = + 0.684                                                                     s.sub.23 = 0.0600                                                   R.sub.3 = + 8.180                                                       C  L.sub.3     d.sub.3 = 0.0375                                                                        n.sub.3 = 1.847                                            R.sub.3 ' = +0.295                                                                      CS = s.sub.34 = 0.1702                                              R.sub.4 = + 1.900                                                          L.sub.4     d.sub.4 = n.sub.4 = 1.500                                            R.sub.4 ' = + 0.516                                                     D               s.sub.45 = 0    Hgl.                                                R.sub.5 = + 0.516                                                          L.sub.5     d.sub.5 = 0.206996                                                                      n.sub.5 = 1.784                                            R.sub.5 ' = - 1.033                                                     __________________________________________________________________________

                                      Example 5                                   __________________________________________________________________________    F = 1.00000 f/3.5 2ω.sub.o = 52° s∞' = + 0.6751            __________________________________________________________________________                               n.sub.d / ν.sub.d                                     R.sub.1 = + 0.34480                                                     A  L.sub.1      d.sub.1 = 0.070785                                                                       1.67790/55.20                                            R.sub.1 ' = + 0.68793                                                                    s.sub.12 = 0.002441                                                R.sub.2 = + 0.31175                                                     B  L.sub.2      d.sub.2 = 0.062974                                                                       1.67790/55.20                                                                          Vgl.                                            R.sub.2 ' = + 0.65413                                                                    s.sub.23 = 0.028070                                                R.sub.3 = + 2.38868                                                     C  L.sub.3      d.sub.3 = 0.014645                                                                       1.72151/29.25                                            R.sub.3 ' = + 0.22715                                                                    CS = s.sub.34 = 0.096414                                           R.sub.4 = + 1.69108                                                        L.sub.4      d.sub.4 = 0.017574                                                                       1.68900/49.46                                            R.sub.4 ' = + 0.24946                                                   D                s.sub.45 = 0       Hgl.                                            R.sub.5 = + 0.24946                                                        L.sub.5      d.sub.5 = 0.059801                                                                       1.74400/44.77                                            R.sub.5 ' = - 1.27733                                                   __________________________________________________________________________

                                      Example 6                                   __________________________________________________________________________    F = 1.00000 f/2.9 2ω.sub.o = 51° s∞' = + 0.6988            __________________________________________________________________________                               n.sub.d / ν.sub.d                                     R.sub.1 = + 0.35015                                                     A  L.sub.1      d.sub.1 = 0.069804                                                                       1.71700/47.99                                            R.sub.1 ' = + 0.90521                                                                    s.sub.12 = 0.001225                                                R.sub.2 = + 0.42220                                                     B  L.sub.2      d.sub.2 = 0.042862                                                                       1.71700/47.99                                                                          Vgl.                                            R.sub.2 ' = + 0.59635                                                                    s.sub.23 = 0.027187                                                R.sub.3 = + 57.93723                                                    C  L.sub.3      d.sub.3 = 0.051434                                                                       1.72830/28.68                                            R.sub.3 ' = + 0.26829                                                                    CS = s.sub.34 = 0.062456                                           R.sub.4 = + 2.74182                                                        L.sub.4      d.sub.4 = 0.044699                                                                       1.54814/45.75                                            R.sub.4 ' = + 0.35520                                                   D               s.sub.45 = 0        Hgl.                                            R.sub.5 = + 0.35520                                                        L.sub.5      d.sub.5 = 0.105930                                                                       1.74400/44.77                                            R.sub.5 ' = - 0.93837                                                   __________________________________________________________________________

                                      Example 7                                   __________________________________________________________________________    F = 1.00000 f/2.9 2ω.sub.o ' = 53.8° s∞' = + 0.6341        __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.39063                                                     A  L.sub.1      d.sub.1 = 0.086215                                                                        1.71700/47.99                                           R.sub.1 ' = + 0.81969                                                                    s.sub.12 = 0.002395                                                R.sub.2 = + 0.34563                                                     B  L.sub.2      d.sub.2 = 0.070649                                                                        1.71700/47.99                                                                          Vgl.                                           R.sub.2 ' = + 0.74651                                                                    s.sub.23 = 0.027541                                                R.sub.3 = + 2.31031                                                     C  L.sub.3      d.sub.3 = 0.020356                                                                        1.78472/25.76                                           R.sub.3 ' = + 0.24823                                                                    CS = s.sub.34 = 0.100585                                           R.sub.4 = + 2.76560                                                        L.sub.4      d.sub.4 = 0.020356                                                                        1.63854/55.38                                           R.sub.4 ' = + 0.31936                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.31936                                                        L.sub.5      d.sub.5 = 0.116151                                                                        1.74400/44.77                                           R.sub.5 ' = - 1.13309                                                   __________________________________________________________________________

                                      Example 8                                   __________________________________________________________________________    F = 1.00000 f/2.4 2ω.sub.o = 54° s∞' = + 0.6649            __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.37875                                                     A  L.sub.1      d.sub.1 = 0.094919                                                                        1.67790/55.20                                           R.sub.1 ' = + 0.72387                                                                    s.sub.12 = 0.002373                                                R.sub.2 = + 0.42194                                                     B  L.sub.2      d.sub.2 = 0.070477                                                                        1.80279/46.76                                                                          Vgl.                                           R.sub.2 ' = + 0.64054                                                                    s.sub.23 = 0.040340                                                R.sub.3 = - 9.72419                                                     C  L.sub.3      d.sub.3 = 0.024916                                                                        1.76180/26.95                                           R.sub.3 ' = + 0.29449                                                                    CS = s.sub.34 = 0.053392                                           R.sub.4 = + 1.62057                                                        L.sub.4      d.sub.4 = 0.018984                                                                        1.46450/65.70                                           R.sub.4 ' = + 0.40696                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.40696                                                        L.sub.5      d.sub.5 = 0.129327                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.97225                                                   __________________________________________________________________________

                                      Example 9                                   __________________________________________________________________________    F = 1.00000 f/2.5 2ω.sub.o = 41° s∞' = + 0.6473            __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.44587                                                     A  L.sub.1      d.sub.1 = 0.113794                                                                        1.67790/55.20                                           R.sub.1 ' = + 2.79332                                                                    s.sub.12 = 0.001737                                                R.sub.2 = + 0.50391                                                     B  L.sub.2      d.sub.2 = 0.061675                                                                        1.74400/44.77                                                                          Vgl.                                           R.sub.2 ' = + 0.68174                                                                    s.sub.23 = 0.069493                                                R.sub.3 = - 1.66399                                                     C  L.sub.3      d.sub.3 = 0.035615                                                                        1.76180/26.95                                           R.sub.3 ' = + 0.32724                                                                    CS = s.sub.34 = 0.109451                                           R.sub.4 = + 4.12005                                                        L.sub.4      d.sub.4 = 0.030403                                                                        1.52341/51.47                                           R.sub.4 ' = + 0.50391                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.50391                                                        L.sub.5      d.sub.5 = 0.074705                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.68174                                                   __________________________________________________________________________

                                      Example 10                                  __________________________________________________________________________    F = 1.00000 f/2.5 2ω.sub.o = 41° s∞' = + 0.6381            __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.44382                                                     A  L.sub.1      d.sub.1 = 0.087078                                                                        1.67790/55.20                                           R.sub.1 ' = + 1.89875                                                                    s.sub.12 = 0.001742                                                R.sub.2 = + 0.45343                                                     B  L.sub.2      d.sub.2 = 0.068791                                                                        1.74400/44.77                                                                          Vgl.                                           R.sub.2 ' = + 0.57095                                                                    s.sub.23 = 0.052247                                                R.sub.3 = - 7.13672                                                     C  L.sub.3      d.sub.3 = 0.067921                                                                        1.72825/28.41                                           R.sub.3 ' = + 0.30524                                                                    CS = s.sub.34 = 0.118774                                           R.sub.4 = + 1.64413                                                        L.sub.4      d.sub.4 = 0.024382                                                                        1.58144/40.86                                           R.sub.4 ' = + 0.38986                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.38986                                                        L.sub.5      d.sub.5 = 0.081853                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.95159                                                   __________________________________________________________________________

                                      Example 11                                  __________________________________________________________________________    F = 1.00000 f/1.4 2ω.sub.o = 32.5° s∞' = + 0.3890          __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.57562                                                     A  L.sub.1      d.sub.1 = 0.191482                                                                        1.73350/51.65                                           R.sub.1 ' = + 3.58024                                                                    s.sub.12 = 0.002659                                                R.sub.2 = + 0.45392                                                     B  L.sub.2      d.sub.2 = 0.120740                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 0.68418                                                                    s.sub.23 = 0.060104                                                R.sub.3 = + 8.30927                                                     C  L.sub.3      d.sub.3 = 0.037233                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.29478                                                                    CS = s.sub.34 = 0.170207                                           R.sub.4 = + 1.90083                                                        L.sub.4      d.sub.4 = 0.037233                                                                        1.50013/61.44                                           R.sub.4 ' = + 0.51680                                                   D                s.sub.45 = 0        Hgl                                            R.sub.5 = + 0.51680                                                        L.sub.5      d.sub.5 = 0.207439                                                                        1.78427/41.30                                           R.sub.5 ' = - 1.03119                                                   __________________________________________________________________________

                                      Example 12                                  __________________________________________________________________________    F = 1.00000 f/1.4 2ω.sub.o = 33° s∞' = + 0.3640            __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.59523                                                     A  L.sub.1      d.sub.1 = 0.206663                                                                        1.71300/53.85                                           R.sub.1 ' = + 5.78329                                                                    s.sub.12 = 0.002691                                                R.sub.2 = + 0.45297                                                     B  L.sub.2      d.sub.2 = 0.142081                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 0.67747                                                                    s.sub.23 = 0.043055                                                R.sub.3 = + 6.87377                                                     C  L.sub.3      d.sub.3 = 0.037673                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.29826                                                                    CS = s.sub.34 = 0.153383                                           R.sub.4 = + 1.85545                                                        L.sub.4      d.sub.4 = 0.061891                                                                        1.50013/61.44                                           R.sub.4 ' = + 0.55003                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.55003                                                        L.sub.5      d.sub.5 = 0.207202                                                                        1.78427/41.30                                           R.sub.5 ' = - 1.12126                                                   __________________________________________________________________________

                                      Example 13                                  __________________________________________________________________________    F = 1.00000 f/1.2 2ω.sub.o = 33° s.sub.∞' = + 0.2895       __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.85142                                                     A  L.sub.1      d.sub.1 = 0.221864                                                                        1.78831/47.37                                           R.sub.1 ' = + 5.64969                                                                    s.sub.12 = 0.005411                                                R.sub.2 = + 0.51816                                                     B  L.sub.2      d.sub.2 = 0.189396                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 1.18551                                                                    s.sub.23 = 0.021645                                                R.sub.3 = + 2.56026                                                     C  L.sub.3      d.sub.3 = 0.140694                                                                        1.91761/21.51                                           R.sub.3 ' = + 0.29990                                                                    CS = s.sub.34 = 0.156928                                           R.sub.4 = + 2.13866                                                        L.sub.4      d.sub.4 = 0.035174                                                                        1.52341/51.47                                           R.sub.4 ' = + 0.44236                                                   D               s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.44236                                                        L.sub.5      d.sub.5 = 0.216453                                                                        1.80801/40.75                                           R.sub.5 ' = - 1.31143                                                   __________________________________________________________________________

                                      Example 14                                  __________________________________________________________________________    F = 1.00000 f/1.3 2ω.sub.o = 18° s.sub.∞' = + 0.3420       __________________________________________________________________________                                n.sub.d / ν.sub.d                                    R.sub.1 = + 0.65893                                                     A  L.sub.1      d.sub.1 = 0.230703                                                                        1.71300/53.85                                           R.sub.1 ' = - 11.97527                                                                   s.sub.12 = 0.004837                                                R.sub.2 = + 0.51229                                                     B  L.sub.2      d.sub.2 = 0.125750                                                                        1.78831/47.37                                                                          Vg1.                                           R.sub.2 ' = + 0.95812                                                                    s.sub.23 = 0.048365                                                R.sub.3 = - 4.24885                                                     C  L.sub.3      d.sub.3 = 0.106404                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.30077                                                                    CS = s.sub.34 = 0.154769                                           R.sub.4 = + 54.26597                                                       L.sub.4      d.sub.4 = 0.096731                                                                        1.51009/63.52                                           R.sub.4 ' = + 0.55848                                                   D                s.sub.45 = 0        Hgl.                                           R.sub.5 = + 0.55848                                                        L.sub.5      d.sub.5 = 0.162024                                                                        1.78831/47.37                                           R.sub.5 ' = - 0.67818                                                   __________________________________________________________________________

The specific examples given above show the wide scope for practical useof the new principles of construction herein disclosed, with respect toa range of relative apertures from f/3.5 (example 5) to f/1.2 (example13) with various useful angular fields which, depending on the purposeof use, may cover an angle from about 18° (example 14) to about 54°(example 8).

The great importance of the new features or rules of construction hereindisclosed, in obtaining improved imageforming performance in five-lensobjectives of the expanded Tessar type herein discussed, is shownparticularly impressively by a comparison of the data of the preformsindicated with the construction data for the precisely correctedobjectives. Reference may be had in this connection to such a datacomparison between example 2 on the one hand and example 7 on the otherhand. Furthermore, from a comparison of the data of example 3 with thedata of example 10, and from a comparison of the data of example 4 withthe data of example 11, it can be clearly noted what slight variationswithin the scope of the new principles of design need only be stilleffected to arrive from a simplified form of construction to anextremely precisely corrected embodiment, by following the inventiveconcepts in accordance with the design rules or features here disclosed.

It may also be pointed out that examples 12 and 13 are particularlyuseful for photographing signals by means of photoelectronic picturetubes. For this purpose, both examples 12 and 13 are corrected with dueconsideration of the action of a selected filter plate (SF) as well asan emulsion support plate (TP), the latter having its rear surfacecoinciding with the image then directly adjacent the photoelectronicrecording layer. In example 12, the filter plate (SF) is developed withflat parallel surfaces arranged at a distance of 0.107637 F axially fromthe last lens vertex R'₅. This plate has an axial thickness d_(SF) of0.080728 F. The emulsion plate (TP) has a thickness d_(TP) of 0.064582F, following at a distance of 0.15905 F behind the filter plate. Bothplates are made of the same type of glass, having an index of refractionof 1.51680, and an Abbe dispersion index of 64.12.

In example 13, both plates are of the same type of glass used in example12, but the spacing and thicknesses are somewhat different. The distanceof the first plate behind the vertex of the last lens surface is0.108226 F, the thickness of this plate is 0.081170 F, the distance fromthe rear surface of this plate to the front surface of the emulsionsupport plate is 0.083876 F, and the thickness of the emulsion supportplate is 0.064936 F.

The following tables I and II give data useful in comparing variousfeatures of the lenses according to examples 1-14 with each other and incomparing them with typical constructions of the prior art. Table Igives numerical values, for comparison purposes, of the indices ofrefraction of the glass of the first two lens elements, indicated in therespective columns headed n₁ and n₂, and the values of the coefficientscalculated therefrom, explained near the beginning of this specificationand identified there as x' and x", in the columns with those respectiveheadings. These respective numerical values are given for all of the 14specific examples embodying the present invention, at the bottom portionof Table I, and are also given, in the top portion of Table I, forcertain selected typical lenses of the prior art. The first line, underthe prior art section, gives the calculated values for British patent476,349. The second and third lines give the calculated values forexamples 1 and 2, respectively, of German gebrauchsmuster 1,882,723,while the fourth and last line of the prior art section of this table,gives the calculated values for the lens disclosed in German patent1,190,216.

In Table II, the numerical values are given, for the same prior artpatents and for the 14 specific examples of the present invention, withrespect to the three special features of the present invention, in therespective columns headed (a) and (b₁) and (b₂), corresponding to thedesignation of these special features of the present invention in theabove discussion.

In stating limits or ranges for the various features of the invention,in the claims or elsewhere, it should be borne in mind that ranges aresubject to a tolerance of plus or minus 5%, as customary in the opticalfield.

                                      Table 1                                     __________________________________________________________________________            The generic concept                                                   Objective                                                                             n.sub.1 x'      x"      n.sub.2 x'      x"                            __________________________________________________________________________    The prior art                                                                 Brit. Pat.                                                                    476.349 1.5890  2.69779 7.27809 1.63750 2.56863 6.59785                       Dt.GM                                                                         1.882.723/1                                                                           1.62041 2.61184 6.82169 1.62041 2.61184 6.82169                       1.882.723/2                                                                           1.62041 2.61184 6.82169 1.62041 2.61184 6.82169                       Dt.Pat.                                                                       1.190.216                                                                             1.6910  2.44718 5.98868 1.6910  2.44718 5.98868                       The invention                                                                 Ex. 1   1.6810  2.46843 6.09314 1.7200  2.38889 5.70679                       2       1.7170  2.39470 5.73459 1.7170  2.39470 5.73459                       3       1.6780  2.47493 6.12526 1.7440  2.34409 5.49474                       4       1.7340  2.36240 5.58092 1.7880  2.26904 5.14852                       5       1.6779  2.47514 6.12634 1.6779  2.47514 6.12634                       6       1.7170  2.39470 5.73459 1.7170  2.39470 5.73459                       7       1.7170  2.39470 5.73459 1.7170  2.39470 5.73459                       8       1.6779  2.47514 6.12634 1.80279 2.24566 5.04297                       9       1.6779  2.47514 6.12634 1.7440  2.34409 5.49474                       10      1.6779  2.47514 6.12634 1.7440  2.34409 5.49474                       11      1.7335  2.36333 5.58531 1.78830 2.26855 5.14633                       12      1.7130  2.40252 5.77212 1.78831 2.26854 5.14626                       13      1.78831 2.26854 5.14626 1.78831 2.26854 5.14626                       14      1.7130  2.40252 5.77212 1.78831 2.26854 5.14626                       __________________________________________________________________________

                  Table II                                                        ______________________________________                                                Values of features                                                              (a)       (b.sub.1)   (b.sub.2)                                     Objective σ.sub.2,1                                                                         B - A       ψ.sub.BA                                  ______________________________________                                        The prior art                                                                 Brit.Pat.                                                                     476.349   +0.1129   -0.62741 Φ                                                                            -0.54540                                      Dt.GM                                                                         1.892.723/1                                                                             -0.3525   +0.18496 Φ                                                                            +0.22512                                      1.882.723/2                                                                             -0.3535   +0.18999 Φ                                                                            +0.23250                                      Dt.Pat.                                                                       1.190.216 -0.2930   +0.25193 Φ                                                                            +0.23202                                      The invention                                                                 Ex. 1     -0.0519   0           0                                             Ex. 2     -0.0625   +0.09113 Φ                                                                            +0.07540                                      Ex. 3     +0.0100   -0.50407 Φ                                                                            -0.56594                                      Ex. 4     -0.0844   -0.29024 Φ                                                                            -0.30776                                      Ex. 5     -0.0503   +0.09027 Φ                                                                            +0.07128                                      Ex. 6     +0.0932   -0.44247 Φ                                                                            -0.43374                                      Ex. 7     -0.0611   +0.08924 Φ                                                                            +0.07385                                      Ex. 8     +0.0539   -0.14841 Φ                                                                            -0.17083                                      Ex. 9     +0.0611   -0.54067 Φ                                                                            -0.55039                                      Ex. 10    +0.0107   -0.50389 Φ                                                                            -0.56540                                      Ex. 11    -0.1182   -0.29008 Φ                                                                            -0.30737                                      Ex. 12    -0.1357   -0.30518 Φ                                                                            -0.32145                                      Ex. 13    -0.2433   +0.03918 Φ                                                                            +0.04265                                      Ex. 14    -0.1252   -0.26603 Φ                                                                            -0.24937                                      ______________________________________                                    

What is claimed is:
 1. An objective of five lens elements, divided intoa front member of three elements all air spaced from each other, and arear member of two lens elements cemented to each other to form a singlecomponent, the two elements of said rear member being of opposite signof power and the neighboring surfaces thereof forming a collectingcement surface;the front lens element of said front member being acollecting lens having unequal front and rear surfaces; the second lenselement being a positive meniscus concave toward the rear and slightlyair spaced rearwardly from said front element; the third lens elementbeing separated from the second element by a dispersing air space, saidthird element being a negative lens having unequal front and rearsurfaces and having its rear surface concave toward the rear and havingits rear surface more strongly curved than its front surface; said frontelement and said second element both being formed of glass having anindex of refraction for the yellow d-line of the helium spectrum whichis within the range limits of 1.6454 and 1.80279; said objective beingcharacterized by the presence of all of the following features: a. therespective radii of the front surfaces of said front element and saidsecond element are so related to each other that the reciprocal of theGardner curvature index for those two surfaces is within the rangelimits of + 0.094 and - 0.244; b₁. said front element and said secondelement are so dimensioned relative to each other that the difference ofthe Petzval curvature portion of the second element minus the Petzvalcurvature portion of the front element is within the range limits of +0.092 Φ and - 0.541 Φ; and b₂. the quotient of said difference of thePetzval curvature portion of the second element minus that of the frontelement divided by the sum of said Petzval curvature portions of thefront and second elements is within the range limits of + 0.076 and -0.566; said reciprocal of said Gardner curvature index being determinedas the quotient of the radius of the front surface of said secondelement minus the radius of the front surface of said front element,divided by the sum of the two radii; and said Petzval curvature portionof each of said front and second elements being determined as thequotient of the power of the respective lens element divided by theindex of refraction of the glass of which the respective element ismade.
 2. An objective as defined in claim 1, wherein the characteristicsof the lens elements and their spatial relationship to each other aresubstantially as indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.9  2ωο = 50°  s∞' = + 0.6341             R.sub.1 = + 0.39000                                                    A  L.sub.1      d.sub.1 = 0.09000                                                                        n.sub.1 = 1.6810                                          R.sub.1 ' = + 0.91453                                                                  s.sub.12 = 0.00140                                                   R.sub.2 = + 0.35150                                                    B  L.sub.2      d.sub.2 = 0.07000                                                                        n.sub.2 = 1.7200                                                                      Vgl.                                              R.sub.2 ' = + 0.70339                                                                  s.sub.23 = 0.02844                                                   R.sub.3 = + 2.35386                                                    C  L.sub.3      d.sub.3 = 0.02055                                                                        n.sub.3 = 1.7850                                          R.sub.3 ' = + 0.25217                                                                  CS = s.sub.34 = 0.10163                                              R.sub.4 = + 2.50017                                                       L.sub.4      d.sub.4  = 0.028999                                                                      n.sub.4 = 1.6380                                          R.sub.4 ' = + 0.32000                                                  D               s.sub.45 = 0       Hgl.                                              R.sub.5 = + 0.32000                                                       L.sub.5      d.sub.5 = 0.115965                                                                       n.sub.5 = 1.7440                                          R.sub.5 ' = - 1.13500                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 3. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000   f/2.7   2ωο = 53°  s∞' = +           0.6341 F                                                                             R.sub.1 = + 0.3910                                                     A  L.sub.1      d.sub.1 = 0.08620                                                                         n.sub.1 = 1.717                                          R.sub.1 ' = + 0.8200                                                                   s.sub.12 = 0.00250                                                   R.sub.2 = + 0.3450                                                     B  L.sub.2      d.sub.2 = 0.07060                                                                         n.sub.2 = 1.717                                                                      Vgl.                                              R.sub.2 ' = + 0.7450                                                                   s.sub.23 = 0.02750                                                   R.sub.3 = + 2.5000                                                     C  L.sub.3      d.sub.3 = 0.02050                                                                         n.sub.3 = 1.785                                          R.sub.3 ' = + 0.2485                                                                   CS = s.sub.34 = 0.100020                                             R.sub.4 = + 2.5000                                                        L.sub.4      d.sub.4 = 0.02900                                                                         n.sub.4 = 1.638                                          R.sub.4 ' = + 0.3200                                                   D               s.sub.45 = 0       Hgl.                                              R.sub.5 = + 0.3200                                                        L.sub.5      d.sub.5 = 0.116025                                                                        n.sub.5 = 1.744                                          R.sub.5 ' = - 1.1350                                                   __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the forgoing specification.
 4. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000   f/2.3   2ωο = 43°  a.sub.∞' = +      0.6383 F                                                                             R.sub.1 = + 0.4440                                                     A  L.sub.1      d.sub.1 = 0.08700                                                                        n.sub.1 = 1.6780                                          R.sub.1 ' = + 1.9000                                                                   s.sub.12 = 0.00180                                                   R.sub.2 = + 0.4530                                                     B  L.sub.2      d.sub.2 = 0.06850                                                                        n.sub.2 = 1.7440                                                                      Vgl.                                              R.sub.2 ' = + 0.5700                                                                   s.sub.23 = 0.05250                                                   R.sub.3 = - 7.2440                                                     C  L.sub.3      d.sub.3 = 0.06677                                                                        n.sub.3 = 1.7280                                          R.sub.3 ' = + 0.3076                                                                   CS = s.sub.34 = 0.12000                                              R.sub.4 = + 1.7160                                                        L.sub.4      d.sub. 4 = 0.02440                                                                       n.sub.4 = 1.5810                                          R.sub.4 ' = + 0.3900                                                   D               s.sub.45 = 0       Hgl.                                              R.sub.5 = + 0.3900                                                        L.sub.5      d.sub.5 = 0.08090                                                                        n.sub.5 = 1.7440                                          R.sub.5 ' = - 0.9530                                                   __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 5. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000   f/1.6   2ωο = 33°   s.sub.∞' =       0.3890 F                                                                             R.sub.1 = + 0.576                                                      A  L.sub.1      d.sub.1 = 0.1915                                                                         n.sub.1 = 1.734                                           R.sub.1 ' = + 3.580                                                                    s.sub.12 = 0.0027                                                    R.sub.2 = + 0.454                                                      B  L.sub.2      d.sub.2 = 0.1207                                                                         n.sub.2 = 1.788                                                                       Vgl.                                              R.sub.2 ' = + 0.684                                                                    s.sub.23 = 0.0600                                                    R.sub.3 = + 8.180                                                      C  L.sub.3      d.sub.3 = 0.0375                                                                         n.sub.3 = 1.847                                           R.sub.3 ' = + 0.295                                                                    CS = s.sub.34 = 0.1702                                               R.sub.4 = + 1.900                                                         L.sub.4      d.sub.4 =  0.0375                                                                        n.sub.4 = 1.500                                           R.sub.4 ' = + 0.516                                                    D               s.sub.45 = 0       Hgl.                                              R.sub.5 = + 0.516                                                         L.sub.5      d.sub.5 = 0.206996                                                                       n.sub.5 = 1.784                                           R.sub.5 ' = - 1.033                                                    __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 6. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000   f/3.5   2ωο = 52°  s.sub.∞' = +      0.6751 F                                                                                                 n.sub.d /ν.sub.d                                       R.sub.1 = + 0.34480                                                    A  L.sub.1      d.sub.1 = 0.070785                                                                       1.67790/55.20                                             R.sub.1 ' = + 0.68793                                                                  s.sub.12 = 0.002441                                                  R.sub.2 = + 0.31175                                                    B  L.sub.2      d.sub.2 = 0.062974                                                                       1.67790/55.20                                                                         Vgl.                                              R.sub.2 ' = + 0.65413                                                                  s.sub.23 = 0.028070                                                  R.sub.3 = + 2.38868                                                    C  L.sub.3      d.sub.3 = 0.014645                                                                       1.72151/29.25                                             R.sub.3 ' = + 0.22715                                                                  CS = s.sub.34 = 0.096414                                             R.sub.4 = + 1.69108                                                       L.sub.4      d.sub.4 = 0.017574                                                                       1.68900/49.46                                             R.sub.4 ' = + 0.24946                                                  D               s.sub.45 = 0       Hgl.                                              R.sub.5 = + 0.24946                                                       L.sub.5      d.sub.5 = 0.059801                                                                       1.74400/44.77                                             R.sub.5 ' = - 1.27733                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 7. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.9  2ωο  = 51° s.sub.∞' = +        0.6988 F                                                                                                   n.sub.d /ν.sub.d                                     R.sub.1 = + 0.35015                                                    A  L.sub.1       d.sub.1 = 0.069804                                                                        1.71700/47.99                                           R.sub.1 ' = + 0.90521                                                                   s.sub.12 = 0.001225                                                 R.sub.2 = + 0.42220                                                    B  L.sub.2       d.sub.2 = 0.042862                                                                        1.71700/47.99                                                                          Vgl.                                           R.sub.2 ' = + 0.59635                                                                   s.sub.23 = 0.027187                                                 R.sub.3 = + 57.93723                                                   C  L.sub.3       d.sub.3 = 0.051434                                                                        1.72830/28.68                                           R.sub.3 ' = + 0.26829                                                                   CS = s.sub.34 = 0.062456                                            R.sub.4 = + 2.74182                                                       L.sub.4       d.sub.4 = 0.044699                                                                        1.54814/45.75                                           R.sub.4 ' = + 0.35520                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.35520                                                       L.sub.5       d.sub.5 = 0.105930                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.93837                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 8. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.9  2ωο  = 53.5°  s.sub.∞' = +     0.6341 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.39063                                                    A  L.sub.1       d.sub.1 = 0.086215                                                                        1.71700/47.99                                           R.sub.1 ' = + 0.81969                                                                   s.sub.12 = 0.002395                                                 R.sub.2 = + 0.34563                                                    B  L.sub.2       d.sub.2 = 0.070649                                                                        1.71700/47.99                                                                          Vgl.                                           R.sub.2 ' = + 0.74651                                                                   s.sub.23 = 0.027541                                                 R.sub.3 = + 2.31031                                                    C  L.sub.3       d.sub.3 = 0.020356                                                                        1.78472/25.76                                           R.sub.3 ' = + 0.24823                                                                   CS = s.sub.34 = 0.100585                                            R.sub.4 = + 2.76560                                                       L.sub.4       d.sub.4 = 0.020356                                                                        1.63854/55.38                                           R.sub.4 ' = + 0.31936                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.31936                                                       L.sub.5       d.sub.5 = 0.116151                                                                        1.74400/44.77                                           R.sub.5 ' = - 1.13309                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 9. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.4  2ωο  = 54°  s.sub.∞ ' = +      0.6649 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.37875                                                    A  L.sub.1       d.sub.1 = 0.094919                                                                        1.67790/55.20                                           R.sub.1 ' = + 0.72387                                                                   s.sub.12 = 0.002373                                                 R.sub.2 = + 0.42194                                                    B  L.sub.2       d.sub.2 = 0.070477                                                                        1.80279/46.76                                                                          Vgl.                                           R.sub.2 ' = + 0.64054                                                                   s.sub.23 = 0.040340                                                 R.sub.3 = - 9.72419                                                    C  L.sub.3       d.sub.3 = 0.024916                                                                        1.76180/26.95                                           R.sub.3 ' = + 0.29449                                                                   CS = s.sub.34 = 0.053392                                            R.sub.4 = + 1.62057                                                       L.sub.4       d.sub.4 = 0.018984                                                                        1.46450/65.70                                           R.sub.4 ' = + 0.40696                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.40696                                                    L.sub.5                                                                              d.sub.5 = 0.129327                                                                      1.74400/44.77                                                       R.sub.5 ' = - 0.97225                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the forgoing specification.
 10. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.5  2ωο  = 41°  s.sub.∞' = +       0.6473 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.44587                                                    A  L.sub.1       d.sub.1 = 0.113794                                                                        1.67790/55.20                                           R.sub.1 ' = + 2.79332                                                                   s.sub.12 = 0.001737                                                 R.sub.2 = + 0.50391                                                    B  L.sub.2       d.sub.2 = 0.061675                                                                        1.74400/44.77                                                                          Vgl.                                           R.sub.2 ' = + 0.68174                                                                   s.sub.23 = 0.069493                                                 R.sub.3 = - 1.66399                                                    C  L.sub.3       d.sub.3 = 0.035615                                                                        1.76180/26.95                                           R.sub.3 ' = + 0.32724                                                                   CS = s.sub.34 = 0.109451                                            R.sub.4 = + 4.12005                                                       L.sub.4       d.sub.4 = 0.030403                                                                        1.52341/51.47                                           R.sub.4 ' = + 0.50391                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.50391                                                       L.sub.5       d.sub.5 = 0.074705                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.68174                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 11. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/2.5  2ωο  = 41°  s.sub.∞' = +       0.6381 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.44382                                                    A  L.sub.1       d.sub.1 = 0.087078                                                                        1.67790/55.20                                           R.sub.1 ' = + 1.89875                                                                   s.sub.12 = 0.001742                                                 R.sub.2 = + 0.45343                                                    B  L.sub.2       d.sub.2 = 0.068791                                                                        1.74400/44.77                                                                          Vgl.                                           R.sub.2 ' = + 0.57095                                                                   s.sub.23 = 0.052247                                                 R.sub.3 = - 7.13672                                                    C  L.sub.3       d.sub.3 = 0.067921                                                                        1.72825/28.41                                           R.sub.3 ' = + 0.30524                                                                   CS = s.sub.34 = 0.118774                                            R.sub.4 = + 1.64413                                                       L.sub.4       d.sub.4 = 0.024382                                                                        1.58144/40.86                                           R.sub.4 ' = + 0.38986                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.38986                                                       L.sub.5       d.sub.5 = 0.081853                                                                        1.74400/44.77                                           R.sub.5 ' = - 0.95159                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 12. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/1.4  2ωο  = 32.5°  s.sub.∞' = +     0.3890 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.57562                                                    A  L.sub.1       d.sub.1 = 0.191482                                                                        1.73350/51.65                                           R.sub.1 ' = + 3.58024                                                                   s.sub.12 = 0.002659                                                 R.sub.2 = + 0.45392                                                    B  L.sub.2       d.sub.2 = 0.120740                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 0.68418                                                                   s.sub.23 = 0.060104                                                 R.sub.3 = + 8.30927                                                    C  L.sub.3       d.sub.3 = 0.037233                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.29478                                                                   CS = s.sub.34 = 0.170207                                            R.sub.4 = + 1.90083                                                       L.sub.4       d.sub.4 = 0.037233                                                                        1.50013/61.44                                           R.sub.4 ' = + 0.51680                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.51680                                                       L.sub.5       d.sub.5 = 0.207439                                                                        1.78427/41.30                                           R.sub.5 ' = - 1.03119                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 13. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/1.4 2ωο  = 33°  s.sub.∞' = +        0.3640 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.59523                                                    A  L.sub.1       d.sub.1 = 0.206663                                                                        1.71300/53.85                                           R.sub.1 ' = + 5.78329                                                                   s.sub.12 = 0.002691                                                 R.sub.2 = + 0.45297                                                    B  L.sub.2       d.sub.2 = 0.142081                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 0.67747                                                                   s.sub.23 = 0.043055                                                 R.sub.3 = + 6.87377                                                    C  L.sub.3       d.sub.3 = 0.037673                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.29826                                                                   CS = s.sub.34 = 0.153383                                            R.sub.4 = + 1.85545                                                       L.sub.4       d.sub.4 = 0.061891                                                                        1.50013/61.44                                           R.sub.4 ' = + 0.55003                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.55003                                                       L.sub.5       d.sub.5 = 0.207202                                                                        1.78427/41.30                                           R.sub.5 ' =0 - 1.12126                                                 __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 14. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/1.2  2ωο  = 33°  s.sub.∞' = +       0.2895 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.85142                                                    A  L.sub.1       d.sub.1 = 0.221864                                                                        1.78831/47.37                                           R.sub.1 ' = + 5.64969                                                                   s.sub.12 = 0.005411                                                 R.sub.2 = + 0.51816                                                    B  L.sub.2       d.sub.2 = 0.189396                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 1.18551                                                                   s.sub.23 = 0.021645                                                 R.sub.3 = + 2.56026                                                    C  L.sub.3       d.sub.3 = 0.140694                                                                        1.91761/21.51                                           R.sub.3 40  = + 0.29990                                                                 CS = s.sub.34 = 0.156928                                            R.sub.4 = + 2.13866                                                       L.sub.4       d.sub.4 = 0.035174                                                                        1.52341/51.47                                           R.sub.4 ' = + 0.44236                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.44236                                                       L.sub.5       d.sub.5 = 0.216453                                                                        1.80801/40.75                                           R.sub.5 ' = - 1.31143                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.
 15. Anobjective as defined in claim 1, wherein the characteristics of the lenselements and their spatial relationship to each other are substantiallyas indicated below:

    __________________________________________________________________________    F = 1.00000  f/1.3  2ωο  = 18°  s.sub.∞' = +       0.3420 F                                                                                                   n.sub.d / ν.sub.d                                    R.sub.1 = + 0.65893                                                    A  L.sub.1       d.sub.1 = 0.230703                                                                        1.71300/53.85                                           R.sub.1 ' = - 11.97527                                                                  s.sub.12 = 0.004837                                                 R.sub.2 = + 0.51229                                                    B  L.sub.2       d.sub.2 = 0.125750                                                                        1.78831/47.37                                                                          Vgl.                                           R.sub.2 ' = + 0.95812                                                                   s.sub.23 = 0.048365                                                 R.sub.3 = - 4.24885                                                    C  L.sub.3       d.sub.3 = 0.106404                                                                        1.84666/23.82                                           R.sub.3 ' = + 0.30077                                                                   CS = s.sub.34 = 0.154769                                            R.sub.4 = + 54.26597                                                      L.sub.4       d.sub.4 = 0.096731                                                                        1.51009/63.52                                           R.sub.4 ' = + 0.55848                                                  D                s.sub.45 = 0         Hgl.                                           R.sub.5 = + 0.55848                                                       L.sub.5       d.sub.5 = 0.162024                                                                        1.78831/47.37                                           R.sub.5 ' = - 0.67818                                                  __________________________________________________________________________

all linear dimensions being expressed in proportion to the equivalentfocal length of the entire lens system considered as unity, the symbolshaving the meanings explained in the foregoing specification.